1. Field of the Invention
The present invention relates to a bending transducer device for generating electrical energy and a circuit module.
2. Description of Related Art
For applications of low power consumption, it is known to use piezoelectric materials for the power supply which generate electrical energy from surrounding energies, in particular from vibrations and deformations (also referred to as “energy harvesting”). The deformations may be converted into electrical energy with the aid of a bending transducer device. Such a bending transducer device which has an elastically deformable support structure and a bearing device in addition to a piezoelectric element is disclosed in published German patent document DE 10 2007 006 994. The piezoelectric element is designed and situated on the support structure in such a way that, due to a deformation of the support structure caused by vibrations, the piezoelectric element is deformable, the support structure being supported vibration-capably in the bearing device. The voltage generated by deforming the piezoelectric element may be picked up via a metal coating on both the top and the bottom of the piezoelectric element. The bending transducer device is part of a circuit module which is usable as an energetically self-sustaining sensor module for measuring a pressure and/or a temperature and/or an acceleration of a tire.
An important criterion for the usability of such bending transducer devices, in particular as a component of an above-described circuit module, is their long service life. During use in a tire in particular, such a bending transducer device is exposed to high mechanical stresses. The bearing, in particular, in which the support structure is supported, is exposed to mechanical stresses. Such stresses are generated by the vibration of the support structure. If the support structure is fixedly restrained, or as in published German patent document DE 10 2007 006 994 supported in a groove of the housing, the service life may be reduced due to abrasion.